Aquatic Diseases

1
Aquatic Diseases

• May 2007
• Reference Aquaculture Science, Rick Palmer

2
Stress and Disease

• Stress is caused by placing fish in a situation
  beyond normal level of tolerance.
• Stress is the increase of glucose levels in the
  blood.
• Low pH and Low Dissolved Oxygen (DO) combined
  with Stress cause hormone release which causes
  Exhaustion!

3
Stressors

• Chemical Stressors Examples
• Poor Water Quality
• Pollution
• Diet Consumption
• Metabolic Waste

4
Stressors (contd)

• Biological stressors (examples)
• Population density
• Other species of fish
• Microorganisms
• Macroorganisms

5
Stressors (contd)

• Physical stressors (examples)
• Temperature
• Light
• Sounds
• Dissolved gases

6
Stressors (contd)

• Procedural stressors (examples)
• Handling
• Shipping
• Disease Treatments

7
Disease Resistance

• Many factors affect how each fish responds to
  potential pathogens.
• The host must be in a susceptible state.
• Weakened immunity
• Stressed

8
Protective Barriers against Infection

• Mucus
• Scales and Skin
• Inflammation
• Anitibodies

9
Effect of Stress on Protective Barriers

• Stress upsets the normal electrolyte sodium,
  potassium, and chloride balance, which results
  in excessive uptake of water in fresh water fish
  and dehydration in salt water fish.

10
Effects of Stress of Protective Barriers (contd)

• Mucus
• Handling removes mucus
• Chemical Stress
• disrupts physical barrier against invading
  organisms
• Scales and Skin
• Handling Stress
• Fighting
• Antibodies
• Temperature Stress
• Can completely stop the immune system

11
Prevention of Stress and Diseases

• Good management prevents Stress
• Good Water Quality
• Good Nutrition
• Sanitation

12
Good Water Quality

• Prevent accumulation of organic debris and
  nitrogenous waste
• Maintain appropriate pH and temperature
• Maintaining DO levels at at least 5 ppm.

13
Good Nutrition

• Feeding high Quality diet
• Feed species specific nutrients

14
Proper Sanitation

• Routine removal of debris
• Disinfect all containers, nets and other
  equipment between groups of fish.

15
Disease Types

• Infectious Diseases
• Parasitic Diseases
• Non Infectious Diseases
• Mostly environmentally based and controlled
  through prevention and good management

16
Infectious Diseases

• Parasitic
• Most frequently caused by protozoa
• Relatively easy to control using fish chemicals
• Bacterial
• Often internal infections
• Require treatment with medicated feeds
• Viral
• Impossible to distinguish from bacterial diseases
  without lab tests.
• Vaccines do not exists for viral diseases
• Fungal
• Usually a secondary problem

17
Parasitic Diseases

• Tapeworms
• Trichodiniasis
• Ichthyophthiriasis
• Monogenetic Flukes

• Anchor Parasites
• Costiasis Disease
• Fish Lice
• Fish Grubs
• Whirling Disease

18
Bacterial Disease

• Bacteremia
• Columnaris Disease
• Enteric Redmouth
• Enteric Septicemia of Catfish (ESC)
• Ulcer Disease of Goldfish
• Chilodonelliasis

19
Viral Diseases

• Channel Catfish Disease
• Infectious Hematopoietic Necrosis
• Infectious Pancreatic Necrosis

20
Determining Presence of Disease

• Look for behavioral changes in fish
• Healthy fish eat aggressively at a regularly
  scheduled time near surface
• Sick fish may appear lethargic
• Sick fish may be lurking in shallow waters not
  appearing to eat
• Dead or dying animals

21
NonInfectious Diseases

• Oxygen Starvation
• Alkalosis
• Acidosis
• Nutritional Deficiency
• Pfiesteria
• Poisoning
• Brown Blood Disease
• Anemia
• Gas Bubble Diseases
• Genetic

22
Determining the Presence of Disease (contd)

• Physical Indicators
• Sores
• Ragged fins
• Abnormal body confirmation
• Distended abdomen
• popeye

23
Importance of daily records

• Daily records should be kept up to date.
• Daily records help to know exactly when a problem
  begins.
• Should include description of behavioral and
  physical signs by sick fish and results from
  water quality tests.